xref: /openbmc/linux/Documentation/hwmon/pmbus.rst (revision 31e67366) 
1Kernel driver pmbus
2===================
3
4Supported chips:
5
6  * Ericsson BMR453, BMR454
7
8    Prefixes: 'bmr453', 'bmr454'
9
10    Addresses scanned: -
11
12    Datasheet:
13
14 http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
15
16  * ON Semiconductor ADP4000, NCP4200, NCP4208
17
18    Prefixes: 'adp4000', 'ncp4200', 'ncp4208'
19
20    Addresses scanned: -
21
22    Datasheets:
23
24	https://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF
25
26	https://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF
27
28	https://www.onsemi.com/pub_link/Collateral/JUNE%202009-%20REV.%200.PDF
29
30  * Lineage Power
31
32    Prefixes: 'mdt040', 'pdt003', 'pdt006', 'pdt012', 'udt020'
33
34    Addresses scanned: -
35
36    Datasheets:
37
38	http://www.lineagepower.com/oem/pdf/PDT003A0X.pdf
39
40	http://www.lineagepower.com/oem/pdf/PDT006A0X.pdf
41
42	http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf
43
44	http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf
45
46	http://www.lineagepower.com/oem/pdf/MDT040A0X.pdf
47
48  * Texas Instruments TPS40400, TPS544B20, TPS544B25, TPS544C20, TPS544C25
49
50    Prefixes: 'tps40400', 'tps544b20', 'tps544b25', 'tps544c20', 'tps544c25'
51
52    Addresses scanned: -
53
54    Datasheets:
55
56	https://www.ti.com/lit/gpn/tps40400
57
58	https://www.ti.com/lit/gpn/tps544b20
59
60	https://www.ti.com/lit/gpn/tps544b25
61
62	https://www.ti.com/lit/gpn/tps544c20
63
64	https://www.ti.com/lit/gpn/tps544c25
65
66  * Maxim MAX20796
67
68    Prefix: 'max20796'
69
70    Addresses scanned: -
71
72    Datasheet:
73
74	Not published
75
76  * Generic PMBus devices
77
78    Prefix: 'pmbus'
79
80    Addresses scanned: -
81
82    Datasheet: n.a.
83
84
85Author: Guenter Roeck <linux@roeck-us.net>
86
87
88Description
89-----------
90
91This driver supports hardware monitoring for various PMBus compliant devices.
92It supports voltage, current, power, and temperature sensors as supported
93by the device.
94
95Each monitored channel has its own high and low limits, plus a critical
96limit.
97
98Fan support will be added in a later version of this driver.
99
100
101Usage Notes
102-----------
103
104This driver does not probe for PMBus devices, since there is no register
105which can be safely used to identify the chip (The MFG_ID register is not
106supported by all chips), and since there is no well defined address range for
107PMBus devices. You will have to instantiate the devices explicitly.
108
109Example: the following will load the driver for an LTC2978 at address 0x60
110on I2C bus #1::
111
112	$ modprobe pmbus
113	$ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
114
115
116Platform data support
117---------------------
118
119Support for additional PMBus chips can be added by defining chip parameters in
120a new chip specific driver file. For example, (untested) code to add support for
121Emerson DS1200 power modules might look as follows::
122
123  static struct pmbus_driver_info ds1200_info = {
124	.pages = 1,
125	/* Note: All other sensors are in linear mode */
126	.direct[PSC_VOLTAGE_OUT] = true,
127	.direct[PSC_TEMPERATURE] = true,
128	.direct[PSC_CURRENT_OUT] = true,
129	.m[PSC_VOLTAGE_IN] = 1,
130	.b[PSC_VOLTAGE_IN] = 0,
131	.R[PSC_VOLTAGE_IN] = 3,
132	.m[PSC_VOLTAGE_OUT] = 1,
133	.b[PSC_VOLTAGE_OUT] = 0,
134	.R[PSC_VOLTAGE_OUT] = 3,
135	.m[PSC_TEMPERATURE] = 1,
136	.b[PSC_TEMPERATURE] = 0,
137	.R[PSC_TEMPERATURE] = 3,
138	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT
139		   | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
140		   | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
141		   | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
142		   | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
143		   | PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
144  };
145
146  static int ds1200_probe(struct i2c_client *client)
147  {
148	return pmbus_do_probe(client, &ds1200_info);
149  }
150
151  static const struct i2c_device_id ds1200_id[] = {
152	{"ds1200", 0},
153	{}
154  };
155
156  MODULE_DEVICE_TABLE(i2c, ds1200_id);
157
158  /* This is the driver that will be inserted */
159  static struct i2c_driver ds1200_driver = {
160	.driver = {
161		   .name = "ds1200",
162		   },
163	.probe_new = ds1200_probe,
164	.id_table = ds1200_id,
165  };
166
167  static int __init ds1200_init(void)
168  {
169	return i2c_add_driver(&ds1200_driver);
170  }
171
172  static void __exit ds1200_exit(void)
173  {
174	i2c_del_driver(&ds1200_driver);
175  }
176
177
178Sysfs entries
179-------------
180
181When probing the chip, the driver identifies which PMBus registers are
182supported, and determines available sensors from this information.
183Attribute files only exist if respective sensors are supported by the chip.
184Labels are provided to inform the user about the sensor associated with
185a given sysfs entry.
186
187The following attributes are supported. Limits are read-write; all other
188attributes are read-only.
189
190======================= ========================================================
191inX_input		Measured voltage. From READ_VIN or READ_VOUT register.
192inX_min			Minimum Voltage.
193			From VIN_UV_WARN_LIMIT or VOUT_UV_WARN_LIMIT register.
194inX_max			Maximum voltage.
195			From VIN_OV_WARN_LIMIT or VOUT_OV_WARN_LIMIT register.
196inX_lcrit		Critical minimum Voltage.
197			From VIN_UV_FAULT_LIMIT or VOUT_UV_FAULT_LIMIT register.
198inX_crit		Critical maximum voltage.
199			From VIN_OV_FAULT_LIMIT or VOUT_OV_FAULT_LIMIT register.
200inX_min_alarm		Voltage low alarm. From VOLTAGE_UV_WARNING status.
201inX_max_alarm		Voltage high alarm. From VOLTAGE_OV_WARNING status.
202inX_lcrit_alarm		Voltage critical low alarm.
203			From VOLTAGE_UV_FAULT status.
204inX_crit_alarm		Voltage critical high alarm.
205			From VOLTAGE_OV_FAULT status.
206inX_label		"vin", "vcap", or "voutY"
207inX_rated_min		Minimum rated voltage.
208			From MFR_VIN_MIN or MFR_VOUT_MIN register.
209inX_rated_max		Maximum rated voltage.
210			From MFR_VIN_MAX or MFR_VOUT_MAX register.
211
212currX_input		Measured current. From READ_IIN or READ_IOUT register.
213currX_max		Maximum current.
214			From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT register.
215currX_lcrit		Critical minimum output current.
216			From IOUT_UC_FAULT_LIMIT register.
217currX_crit		Critical maximum current.
218			From IIN_OC_FAULT_LIMIT or IOUT_OC_FAULT_LIMIT register.
219currX_alarm		Current high alarm.
220			From IIN_OC_WARNING or IOUT_OC_WARNING status.
221currX_max_alarm		Current high alarm.
222			From IIN_OC_WARN_LIMIT or IOUT_OC_WARN_LIMIT status.
223currX_lcrit_alarm	Output current critical low alarm.
224			From IOUT_UC_FAULT status.
225currX_crit_alarm	Current critical high alarm.
226			From IIN_OC_FAULT or IOUT_OC_FAULT status.
227currX_label		"iin", "iinY", "iinY.Z", "ioutY", or "ioutY.Z",
228			where Y reflects the page number and Z reflects the
229			phase.
230currX_rated_max		Maximum rated current.
231			From MFR_IIN_MAX or MFR_IOUT_MAX register.
232
233powerX_input		Measured power. From READ_PIN or READ_POUT register.
234powerX_cap		Output power cap. From POUT_MAX register.
235powerX_max		Power limit. From PIN_OP_WARN_LIMIT or
236			POUT_OP_WARN_LIMIT register.
237powerX_crit		Critical output power limit.
238			From POUT_OP_FAULT_LIMIT register.
239powerX_alarm		Power high alarm.
240			From PIN_OP_WARNING or POUT_OP_WARNING status.
241powerX_crit_alarm	Output power critical high alarm.
242			From POUT_OP_FAULT status.
243powerX_label		"pin", "pinY", "pinY.Z", "poutY", or "poutY.Z",
244			where Y reflects the page number and Z reflects the
245			phase.
246powerX_rated_max	Maximum rated power.
247			From MFR_PIN_MAX or MFR_POUT_MAX register.
248
249tempX_input		Measured temperature.
250			From READ_TEMPERATURE_X register.
251tempX_min		Minimum temperature. From UT_WARN_LIMIT register.
252tempX_max		Maximum temperature. From OT_WARN_LIMIT register.
253tempX_lcrit		Critical low temperature.
254			From UT_FAULT_LIMIT register.
255tempX_crit		Critical high temperature.
256			From OT_FAULT_LIMIT register.
257tempX_min_alarm		Chip temperature low alarm. Set by comparing
258			READ_TEMPERATURE_X with UT_WARN_LIMIT if
259			TEMP_UT_WARNING status is set.
260tempX_max_alarm		Chip temperature high alarm. Set by comparing
261			READ_TEMPERATURE_X with OT_WARN_LIMIT if
262			TEMP_OT_WARNING status is set.
263tempX_lcrit_alarm	Chip temperature critical low alarm. Set by comparing
264			READ_TEMPERATURE_X with UT_FAULT_LIMIT if
265			TEMP_UT_FAULT status is set.
266tempX_crit_alarm	Chip temperature critical high alarm. Set by comparing
267			READ_TEMPERATURE_X with OT_FAULT_LIMIT if
268			TEMP_OT_FAULT status is set.
269tempX_rated_min		Minimum rated temperature.
270			From MFR_TAMBIENT_MIN register.
271tempX_rated_max		Maximum rated temperature.
272			From MFR_TAMBIENT_MAX, MFR_MAX_TEMP_1, MFR_MAX_TEMP_2 or
273			MFR_MAX_TEMP_3 register.
274======================= ========================================================
275